Metal Ducting Connector / Coupling The male spigot fits inside our range of galvanised spiral pipe, Kair plastic pipe, and other female coupling products. Rubber Seals Fast and easy to install: Allows installation without sealant. Push-fit rubber seal coupling designed to join lengths of spiral ducting. Saves money and time on extra installation steps - Can be twisted and adjusted with tightness unaffected. Need further information? Contact our friendly i-sells team for advice on exactly what you need for your project.